Rename GPIO_SUPPORT to GPIO

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/brppt2_defconfig b/configs/brppt2_defconfig
index f362aea..d307971 100644
--- a/configs/brppt2_defconfig
+++ b/configs/brppt2_defconfig
@@ -4,7 +4,7 @@
 CONFIG_ARCH_MX6=y
 CONFIG_SPL_LDSCRIPT="arch/arm/cpu/u-boot-spl.lds"
 CONFIG_SYS_TEXT_BASE=0x17800000
-CONFIG_SPL_GPIO_SUPPORT=y
+CONFIG_SPL_GPIO=y
 CONFIG_SPL_LIBCOMMON_SUPPORT=y
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
 CONFIG_SYS_MALLOC_F_LEN=0x1000